const Question = require('../models/questions')

class QuestionsCtl {
  // 检查问题存在与否
  async checkQuestionExist (ctx, next) {
    const question = await Question.findById(ctx.params.id).select('+questioner')
    if (!question) { ctx.throw(404, '问题不存在！') }
    ctx.state.question = question
    await next()
  }
  // 查询问题列表
  async find(ctx) {
    const { per_page = 10 } = ctx.query;
    const page = Math.max(ctx.query.page * 1, 1) -1
    const perPage = Math.max(per_page * 1, 1)
    const q =  new RegExp(ctx.query.q)
    ctx.body = await Question
      .find({ $or: [{ title: q }, { description: q }] })
      .limit(perPage)
      .skip(page * perPage)
  }
  // 查询特定问题
  async findById(ctx) {
    const { fields='' } = ctx.query;
    const selectFields = fields.split(';').filter(f => f).map(f => ' +'+f).join('')
    const question = await Question.findById(ctx.params.id).select(selectFields).populate('questioner topics')
    ctx.body = question
  }
  // 创建问题
  async create(ctx) {
    // 校验参数
    ctx.verifyParams({
      title: { type: 'string', required: true },
      description: { type: 'string', required: false }
    })
    const question = await new Question({...ctx.request.body, questioner: ctx.state.user._id}).save()
    ctx.body = question;
  }
  // 检查是否是当前问题的提问者
  async checkQuestioner(ctx, next) {
    const { question } = ctx.state
    if (question.questioner.toString() !== ctx.state.user._id) {
      ctx.throw(403,'没有权限')
    }
    await next()
  }
  // 更新问题
  async update(ctx) {
    // 校验参数
    ctx.verifyParams({
      name: { type: 'string', required: false },
      avatar_url: { type: 'string', required: false },
      introduction: { type: 'string', required: false }
    })
    await ctx.state.question.updateOne(ctx.request.body)
    ctx.body = ctx.state.question
  }
  // 删除问题
  async delete(ctx) {
    await Question.findByIdAndRemove(ctx.params.id)
    ctx.status = 204;
  }
}

module.exports = new QuestionsCtl()